| SplitInIsleAndHoles | Sortes the Sub-Polygons in single Isles (including their holes) |
| SplitInIsleAndHoles(Double) | Sortes the Sub-Polygons in single Isles (including their holes) |
| SplitInIsleAndHoles(IPCBIWindow, IODBLayer) | Check all subpolygons for holes and isles, make a list of new surfaces for each isle with own holes. |